1. Field of the Invention
The present invention relates to a method of optimizing a hard disc drive, and more particularly, to an optimizing method, which revises parameters of the hard disc drive by periodically performing a retry of the hard disc drive when the hard disc drive is in an idle state and using the accumulated result of the retries, an apparatus suitable for the method, and a recording medium suitable for the method.
2. Description of the Related Art
A hard disc drive can be used in various environments, however, when the hard disc drive is used in poor surroundings, for example, a tropical area or an arctic area, functioning of the hard disc drive may severely worsen. Also, the functioning of the hard disc drive may worsen due to a change in mechanical characteristics over a certain period of time. Therefore, it is important to optimize the hard disc drive so that the hard disc drive can always operate with excellent performance despite a change in conditions and/or the time used.
Performance of the hard disc drive is optimized by adjusting various parameters of a controlling operation of the hard disc drive, and especially, parameters of a read/write channel. Examples of these parameters are a cutoff frequency, a bandwidth, an FIR (Finite Inverse Response) filter gain, etc.
The hard disc drive is shipped after a rough optimization is performed in each zone and head at a given temperature, usually at normal temperatures, in a burn-in test process. Since this rough optimization is performed in a limited time period, a limited environment of a chamber, and at a limited temperature, it is nearly impossible to cover every environment where the hard disc drive can be installed.
When the hard disc drive is operated by using parameter values calculated in the burn-in test process, an error rate increases if the burn-in test environment does not match an environment in which the hard disc drive is used. Head characteristics of the hard disc drive may decrease due to use, and mechanical characteristics of the hard disc drive may change according to the time used. Optimization of the hard disc drive in the environment in which it is used is necessary for a low error rate.
For this purpose, in the burn-in test process, after testing many drives in low and high temperature conditions, a temperature dependent statistical distribution of each parameter is obtained. Thereafter, an approximate optimization is performed by applying the statistical distribution according to the temperature condition in which the hard disc drive is actually used.
In detail, in a prior hard disc drive, an ambient temperature is measured by a temperature sensing unit, a difference between the measured temperature and a temperature in the burn-in test process is calculated, and parameter values, which are adjusted in the burn-in test process in relation to the temperature difference, are readjusted by applying a temperature dependent statistical distribution. At this time, the parameters applying the temperature dependent statistical distribution are usually limited to a few basic parameters of all of the parameters. Optimizing methods are disclosed in Korean Patent Publication No. 2002-67794 (laid open Aug. 24, 2002) and No. 1999-71161 (laid open Sep. 15, 1999) by the present applicant.
However, since a prior optimizing method is simply performed by the temperature dependent statistical distribution, appropriate optimization cannot be performed to correspond to characteristic differences of each apparatus and/or a change of the hard disc drive according to time. Also, since optimization is performed only for a few basic parameters of all of the parameters, exact optimization cannot be performed.
The hard disc drive may be optimized through an error recovery process, i.e., a retry. Data written in the hard disc drive is written per sector unit. If a data read/write of a desired sector fails in a data read/write process, the hard disc drive retries to read/write the data in the desired sector by a disk's rotation, and this is called a retry. In this process, the read/write is retried after some parameters are adjusted. Such a retry method is disclosed in Korean Patent Publication No. 2003-25688 (laid open Mar. 29, 2003) by the present applicant.
However, this retry method is only performed when the hard disc drive fails to read/write data in the desired sector, and since the number of retries is limited in most cases, the retries frequently fail in actual cases; therefore, appropriate optimization of the hard disc drive is not performed.